Projectiles having a substantially non-deformable casing, for example, a casing made out of steel or being provided with a sabot made, for example, out of a light metal alloy, can be provided in the region of the connection between the shell and the casing with an annular groove extending around the projectile, in which the shell casing in the region of the openmouth is crimped, to thereby from a form-locking connection, which can only be overcome by a sufficiently strong predetermined expelling force. The rigid connection must be able to withstand high braking forces, particularly with ammunition for rapid-fire weapons, which appear as an impact shock during the introduction of the cartridges into the loading chamber.
In a projectile, which is formed in the region of its connection to the shell proper out of plastic material, the connection cannot be in the form of a crimp connection because of the problems which are inherent with the materials to be joined which have not the required strengths. Therefore, another type of method must be selected.
With break-up ammunition the described manual steps for producing a connection include the application of a glueing or synthetic liquid substance which hardens and which is applied by means of a brush to the inner surface of the throat of the cartridge case, whereafter a fragmentation shell, having a roughened plastic tail section, is pressed in. The following drawbacks are present in the ammunition of the state of the art:
In order to obtain a good connection which will withstand the application of a strong expelling force, the glueing or synthetic substance must be applied frequently in large amounts. This, in turn, causes considerable soiling, which in turn requires a post-cleaning step. This manual step is uneconomical because of the aimed for production intensity which requires numerous control conditions; this step can also become harmful to the personnel carrying out the manual step.